Add default and v1 subcommands to export
Add default and v1 subcommands to export

Start of the refactoring process to separate v1 and 
v2 processes within export command. 

The options are separated into argument groups
for better readability of the help message.

Co-authored-by: Kairsten Fay <kairsten.fay@gmail.com>
Update export arguments

Add `SUPPRESS` to `--v1` option to hide it from 
public users.

Update `v1_config` to only include `--auspice-config`
since export v1 does not support additional options.
nextstrain/augur,blab/nextstrain-augur,nextstrain/augur,nextstrain/augur